Pumping apparatus



9, 1940- J. M. BART-HOLQMEW 2.2215355 PUMPING APPARATUS 3 Sheets-Sheet 1 Filed Dec. 2, 1935 w. M m4 1 5 m M fiu- M U 90 E 4 Nov. 19, 1940- J. M. BARTHOLOMEW 2,221,355

PUMPING APPARATUS Filed D80. 2, 1935 3 Sheets-Sheet 2 fizzy.

Nov. 19, 1940. I g .1. M. BARTHdLOMEW 2,221,355

PiIMPING APBARATUS v Filed Dec. 2, 1935 3 Sheets-Sheet-3 v 34 -35 33 2a so any.

Pia-mi Nov. 19, 1e40 a 2,221,855

.UNITED STATES PATENT OFFICE Jess M. 1116-. assignor to Sullivan Machinery Company, a corporation of Massachusetts Application December 2, 1935,, Serial No. 52,55: 19 Claims. (Cl. 230-4) My invention relates to pumping apparatus, tem, operate for long periods unloaded and use and more particularly to pumping apparatus considerable quantities of operating medium having special controlling means whereby the without benefit, the stop-and-start system of same may be caused to operate with maximum operationis obviously the more economical; and,

efliciency irrespective of the mode employed for further, very material economy can be effected it 5 maintaining its output within the desired limits. re-starting is deferred for a maximum possible From another aspect, it relates to improved pilot period. If the pumped fluid be air and the maximechanism especially adapted to, but not exmum desired operating pressureis 100 pounds per i clusively limited to, pump control. square inch, it is possible, without undue loss of Under certain conditions, where a relatively efficiency and-with sound economy for the en- 10 uniform and high demand prevails (near the tire system, to a1low the pressure to drop permaximum pumping capacity), it is desirable to haps to 80 pounds pe square inch before reoperate pumping apparatusand particularly, starting the compressor, though not exclusively, reference is here had to- Now it will be evident that it may be highly l5 compressors-upon a' system in which there is no desirable to operate the same plant selectively on stopping of the compressor drive, but instead an either oi? the two systems specified, employing interruption of the delivery of fluid by the conthe one during day shifts and the other at night tinuously driven pmnping apparatus for so long I or on holidays; and it will be noted that it would a time as may be requisite to reduce the quanbe desirable to change the minimum pressure tity of previously pumped fluid to the desired limit although not the maxlmmn presure limit, 20

minimum value. inmalring he changefromtheonesystemtothe- Under other circumstances, where the demand other. V

for pumped fluid is relatively low and accordingly It is an object of my invention to provide an the quantity of fluid pumped within a unit of improved apparatus in which the change-over operating time is likely to sufllce for a considerfrom one system to the other is automatically 25 ably longer period of demand, it is desirable, to accompanied by a change in the minimum presreduce wear and to economize 'on' operating sure limit. It is a further object of my invention medium, to interrupt the drive of the pumping to provide in such an apparatus improved means apparatus completely and to bring the same to whereby the change in the minimum pressure a stop until such time as the consumption of the limit does not appreciably aflfect the maximum 30 pumped fluid again makes necessary further pressure limit. It is a still further object of my pumping to preclude the reduction of the availinvention to-provide an improved pumping apable pumped fluid to less than a desired minimum. paratus in which a single pilot apparatus may when operating upon the flrst system, it is conbe automatically adjusted, in making the changesidered good practice to efiect interruption and 7 over irom the one operating system to the other, 35 resumption of the pumping'apparatus upon comto perform its function produced on attainment paratively small changes in the available quanof a predetermined minimum presure at distlty oi pumped fluid. For example, in the case tinctly difierent minimum pressures, without alwhere the pumped fluid is air and the pumping tering materially the point oi functioning at 9.

=40 apparatus is an air compressor, and the maximaximum pressure.' It is another object of my 40 mum desired value is, let us say, 100 pounds per invention to provide an improved apparatus 01 square inchat which point unloading would be the character set forth, in which devices having resorted to, preclude further delivery of fluidsubstantially the same maximum control presit would be desirable to effect re-loading and a sures and widely differing minimum control r ption of the delivery of pumped fluid after pressures may be selectively connected into con- 5 Jigsaw oi perhaps flve pounds. This is true ,trolling relation to the system when a change in be because the rateoi consumption of pumped basic type of control of the system is effected. fluid is rapid and because itis desirable to provide A still further object of the invention is to proasneariy a uniionn'pressure, ordinarily, at the vide an improved, adjustable presponsive sb pumped-fluid-utilizlng devices as pomible. pilot mechanism. Still another object of my in- Under other circumstances, where-tor exvention is to provide an improved snap action ample during a night shiit 'there might be compilot mechanism having ted therewith paratively little demand for pumped fluid and a means for varying the lower snap joint while leavcompressor adequate to supply the daytime needs mg the higher snap point unchanged. and prowould, ii operated on the load-and-unload sysviding for said improved pilot mechanism means 55 for automatically v rying the snap point when the basic system of control oithe apparatus as a whole is changed. Still another object of the invention is to provide an improved pilot means mum value without varying the'maxlmum value, when the system of which said pilot mechanism forms a part is shifted from once! the operating systems previously mentioned to I the other. Other objects and advantages of the invention will hereinafter more fully appear.

. controlling apparatus therefor.

Fig. 3 is a view, also on an enlarged scale, and in vertical section, showing a portion of the adjustable pilot means employed in the system of showing a detail 01' construction.

Fig. 1.

Fig. 4 is a vertical, fragmentary section on. the p1aneofthelineHofFig.3.

Fig. 4 is a detail showing a possible modification.v

Fig. 5 is a. fragmentary view showing details of a modified apparatus for eil'ecting a transfer from one operating system to another.

Fig. 6 is a. horizontal section on the plane of themes-sornaabutw ththeswltcnarm in a diiierent position.

Fig. 7 is a fragmentary horizontal section on theplane oi. theline 1-1 of Fig. 5 and with the cam shown in the position corresponding to the position of the switch'arm inFlg. 6.

Fig. 8 is a view, partially in side elevationand' partially diagrammatic, 01 a system similar to that with which the K elusive is employed, but employing a still dialer-- ent type of control for the pilot means.

Fig. 9 is a fragmentary view showing a detail of oonstmetion of the apparatus of Fig. 8.

- Fig. 10 is a fragmentary horizontal section on theplaneoi'thelinell-ll oil'ig. 9. f

Fig. 11 is an enlarged view, partially in section and with parts broken away, showing details of another form of pilot apparatus. 7

Fig. 12 is a fragmentary section on a plane parallel to the viewin Fig. 11, showingdetails of construction.

a Fig. 13 is a fragmentary view irom below,

. Fig. His a small transverse view on the-plane oi the line ll-ll of Fig. 11, showing a detail of construction. v

Fig. 15 is a partially di rammatic and partlally side elevational view of a system employing'a pilot apparatusgoi the character shown in Figs. 11 to 14, inclusive. Referring flrst'to the apparatusillustrated in I Fig. 1, it will be-observed that a suitable driving motor I arranged to receive current from power lines 2 upon the closure of a main line switch I. is connected in driving relatlonwlth a compressor 4, herein oi the multl-cyllnder type. This compressor is provided, for each cylinder thereof, wlthintake and discharge mechanism as illustrated in Fig. 2. This mechanism includes a.

having control mechanism associated therewith operative to alter the miniapparatusoil 'iga3to'lin- The compressor cylinders deliver, through connections |2,.l2, to a common discharge connection l3, which leads herein to a. receiver II, the pressure from within which is conducted through a pipe ii to a controlling valve mechanism IS ineluding a lower receiver-pressure-fllled chamber l'l, an intermediate chamber l8 connected by a pipe 19 with a cylinder Ill in which the plunger 9 reciprocates, and an upper, vented chamber 2i having an atmospheric or other suitable vent connection 22. Oppositely facing valves 23 and I 24 are adapted, in the position of the parts shown in Fig. 2, to open communication between the line l5 and the pipe l9, and in the reversed (raised) position of the valves 23 and 213, to interrupt communication between pipes l5 andl9 and open communication between pipe I! and the vent 22. Springs 25 and are providedat opposite sides of. the valves, and these valves may be separately formed and have stems abutting each other, as at 21. An operating plunger 28 having a heavy spring 29 normally maintaining the valve 24 seated and the valve 23 open, is adapted to control the position of the valves.

- This plunger constitutes the core of an electromagnetic device, and is sin-rounded by a solenoid or magnet winding- Ill; and upon energization of this winding, valve 24 is unseated and valve 23 is allowed to close. when, however, the winding III is not energized, the spring 29, the weight of the plunger '28, etc. seat the valve 23 and 'hold it closed, and unseat ,the valve 23, and thereby place the unloading plungers 9, since both are supplied thro h the connection is and its extension Ill, with recelverpressure substantially simultaneously, under-pressure, compressor unloaded. V

Now, from the description so 'iargivemit will be evident that the compressor 4 is adapted to be driven when its driving motorl is supplied with current, but'that it will not be loaded until thewindinglllisenerglzed; andso,unlessthe winding ll be energized before the compressor is started, the compressor will start unloaded, which is a very desirable condition.

The switch lisotthenormallyopen type and is adapted to be closed by a solenoid 32. The solenoid 32 isv connected at one end by a conductor II with the my II of a transformer ll whose primary 3 connected across two of the power llnesi. The other end of the solenoid 32 is connected to a conductor 31.

The magnet winding is connected at one end to a conductor I8 and at its other end to a conductor 89. The conductor 3! leadsirom a time delay relay oi well known commercial con- .structlon, marked 'IDR in the drawings, and the and so hold the 5 of the maximhm sponsor timeintervalclosesacircuitbetweentheconductors55and55. Asthisiunctionandthe structure of these devices are well known, and this time delay relay may assume 5 manyforms'and is a standard article oimanufaeturewhichcanbeboughtintheopenmarket, further description oi its mode of operation is unnecessary. Beyond its point of conection with the conductor 5|, the conductor 51 is connected to other conductors 52 and 55 respectively. These lead respcctivelyto contacts-55 and 55 ina socalled transfer switch 55, and this transfer switch also is provided with other contacts 51 and 55 and with a movable contact 55, which may be caused, in one position 0! the switch, to connect the contacts 55 and 51, and in an opposite posi-' tion to connect the contacts 55 and 55. The contact 55 is connected by a conductor 55 and a further conductor 5| to the end of the trans-- former secondary 55 to which conductors 55 and 55 are not connected. The contact 51 has a conductor 5 connected thereto, to which the conductor 3 leads, and also is connected, by a conductor 53, to one of the contacts of a Mercold switch M whose other contact is connected by a conductor 55 to the conductor 5|. The Mercoid" switch forms a portion of a pilot mechanism, generally designated P. This pilot mechanism, best illustrated in Fig. 3, comprises a diaphragm 55 which is subjected, upon its exterlor, to receive pressure through a connection 55, which opens into a chamber 51 surrounding the diaphragm 55. It will be noted that the diaphragm 55 is operatively connected to and tends to eflfect a swinging movement of an arm 55 about a. pivot 55 provided by a casing 55 housing the component elements of the pilot mechanlsm- P. The range of movement of the arm 55 islimitedbystops 5| and 52. Thearm 55 formsa 0 portion of a trigger or snap mechanism, generally designated 55, and is subjected to the endwise pressure of a spring 55 whose compression may be varied by varying the projection within the casing 55 of a plunger 55, which provides a reaction point for the end of the spring 55 remote from the arm 55. A link 55 connects the free end of the arm 55 with the switch 15, which is of the so-called Mercoid type and contains mercury. as at 51, which in the tilted podtion of the switch shown in Fig. 3 establishes an electric circuit between the conductors and 55. The plunger 55 is disposed substantially in alinement with the pivot 55, and accordingly the spring 55 exercises little eflect upon the movement of the 55 arm 55 when said am is in de position, i. e. as shown in Fig. 3. A primary control spring 58 acting in opposition jto the diaphragm 55, provides substantially exclusive control of the movement of the arm 55 upwardly, and provides 60 a major load thereon; and the adjustment of the compression of the spring 55 varies the maxi mum pressure limit of operation of the apparatus P. when the arm 55 is in its upwardly tilted position, which it assumes upon the attainment which position the switch 55 is swung about the pivot m and the mercury 51 conductors 55 and 55 and opens the circuit between said conductors), the spring 55 exercises a very substantial force and plays a very material part in determining the pressure at which movement of the arm 55 in the downward direction shall take place. It will be foimd that the pressure range between the opening and closing neitheswitchllcanbemarkedlyvariedsimpb desired receiver pressure (inaway from the byvarrinsthe on ofthespring 55, without materially varyin the pressure at which openingoitheswitchwilioccur: andtheplunger 55, upon being variously projected longitudinally, will provide for the n variation in the 5 compression of the spring 55 to secure a large or small pressure difference; as may be desired, in the pressure at which the spring 55 will be effective to cause re-closing oi the switch M.

Many ways of varying the projection of the 10 plunger 55 may be employed. In Figs. 1, 3 and 5. one simple and somewhat tic mode oi accomplishing this function is illustrated. It will be noted that the transfer switch 55 is provided with a sprocket 15 turning therewith l5 and connected by a chain 1| with a sprocket 12 mounted upon a shalt 15 whose axis is at right 7 angles to the axis of the plunger 55. The shaft 15 carries a cam 15 which, in the ofl" position (the intermediate position) of the transfer'switch 20 55, simply holds the plungerv 55 in the position shown in Fig. 3. Upon movement of the transfer switch 55 to connect the contacts 55 and 51, the 'cam 15 will project theplunger 55 substantially to the right in Fig. 3, and then hold it there. 25 Upon movement of the transfer switch from the position shown in Fig. l to a position connecting the contacts 55 and 55, no movement of the cam 15 afiecting the position of the plunger 55 will take place. It will be noted that the 0 cam 15 has a long, low arcuate portion 15 and a quadrantal high operating portion 11.

- If it be desired to vary the pressure difference produced by moving the cam 15 into pin-protruding position, this may be easily accomplished 35 by providing a cam of varying radial dimension and sliding the cam longitudinally along its shaft, of courseproviding suitable holding means to maintain it in desired position. Such an arrangement is shown in Fig. 4 in which the cam 40 portion 11 is sloping and the cam is movable by the adjusting mechanism 18, held in different positions by the pin devices 15, to provide different movements, as may be desired, of the plunger 55. This mechanism is merely illustrative of a wide variety of devices which may be employed. 7

The mode of operation of the apparatus so far described will bereadily understood from whaL has been said. In Fig. 1 the apparatus is shown 5 with the parts in the relative positions they would occupy before the motor is started. The switch 55 is in neutral position and must be moved in one direction or the other to place the system in operation. It will be borne in mind that in the 55 position oi the parts shown, the solenoid 35 is deenergized and accordingly the compressor is unloaded. Depending upon which direction the switch mechanism 55 is turned, the system will operate either with continuous running of the 60 compressor and periodic loading and unloading, or with intermittent running of the compressor and starting each time unloaded. Continuous running of the compressor will take place when switch 55 is moved counter-clockwise from the 65 position shown in Fig l. Intermittent running of the compresor will be the mode of operation upon movement of the switch clockwise in Fig. 1. It should be borne in mind that inthe position of the plunger 55 shown in Fig.-3 the pilot mechanism will eflect opening of the switch at a maximum pressure, let us say, of 1 00 pounds, and

closing of the switch again when the pressure falls oil, let us say, to 95 pounds; while with the plunger 55 projected into the casing 55, as

occur when the cam portion Ti contacts the end of the plunger, the switch will open still at approximately 100 pounds, but will not close again until the pressure falls off perhaps to 80 pounds.

Now let us consider that the operatorwishes to start 'up the system and tocause the same to operate on the continuous running, loading-andunloading system. He will therefore turn the switch 46 through 90? counter-clockwise in Fig. 1 and cause the contact 49 thereon to connect the contacts 45 and 48. Immediately, current will flow from the transformer secondary 34 through the circuit including the conductor i, conductor 50, contact 48, contact 49, contact 45, conductor 43, conductor 31, solenoid 32 and conductor 33; and the switch 3 will close and the motor will start. Simultaneously with the establishment of the circuit through the switch operating solenoid 32,;a circuit will be established includingthe transformer secondary 34, conductor 5i, conductor 50, contacts 48, 49 and 45, conductor 43}, conthe switch 46 with the contact 49 in lower poslductor 31, conductor 4|, the time delay relay operating circuit, and conductor 49; and the time delay relay will close its internal contactor after a. predetermined time interval. Whenthe time delay for which the time 'delay relay is set, has elapsed, current will likewise flow through a circuit including the transformer secondary 34, the conductor 5|, conductor 54, switch M if the latter be closed, conductor 53, conductor 38, solenoid 30, conductor 39, time delay relay TDR, and conductor 40. It will therefore be evident that only when the switch M is closed will the compressor load; and it will further be evident that the compressor will 1 d and unload under the control of the moveme ts of the switch M as long as the system is set to operate in the manner mentioned, that is, as long as the switch 46 .remains in the position last described. During this operation, loading and unloading will be brought about as a result of the pressure changes, loading occurring when the pressure drops to, say, 95 pounds, and unloading occurring when the pressure rises to 100 pounds.

when it is desired to operate on the stop-andstart system, the operator, instead of positioning tion, will ,move the switch-46 to cause the contact 49 to connect the contacts 41 and. Then the following operations will occur. Only when the switch M is closed will anything take place.

-- When the switch M is closed, however, a circuit will be established including transformer secondary 34, conductor 5|, conductor 54, mercury 81, conductor 53, conductor 52, contacts 41, 49 and 44, conductor 42, conductor 31, solenoid 32, and conductor- 33; and the; motor switch 3 will then be closed. This will start the motor. Concurrently with the establishment of the circuit Just described, there will also be established a circuit including transformer secondary 34, conductor 5|, conductor 54, mercury 61, conductor i3, conductor 52, contacts 41, 49 and 44, conductor 42, conductor 31, conductor 4|, the operating device of the time delayrelay, and conductor 40. Accordingly, the time delay relay will be set in -.operation concurrently with the closing of the 11, conductor I3, conductor 38, winding 38, conmotor circuit. "Then, after the time lapse compelled by the time delay relay, a further circuit .will be established including the transformer secondary I4, conductor 5|, conductor 54, mercury ductor 3 8, the time delay relay, and conductor 40; and the compressor will be. loaded due to the movement of the valves 23 and 24 respectively to Now it is important to note that as the switch.

48 was moved to position the contact .49 in engagement with contacts 41 and 44, the sprocket 10, chain H, and sprocket I! moved the cam 14 and brought its high point 11 into engagement with the plunger 65, and forced that plunger inwardly, thereby increasing the compression of the spring 64 and making necessary a much greater receiver pressure drop before the switch M would move from open to closed position. Accordingly, when rising receiver pressure has once caused opening of the switch M. and stopping of the compressor through the breaking of the circuit through the solenoid 32, a much more marked pressure drop will be necessary before the switch M will reclose, say, a drop from 100 to 80 pounds. However, due to the special relation of the parts, this result, which follows upon the protrusion of the plunger 65 into the casing 68, will not materially aifect the upper pressure limit of 100 pounds.

From the description given, it will be obvious that I have provided an apparatus adapted effectually to control the output of a pumping sys-I tem, either by loading or unloading upon the occurrence of close pressure difl'erentials, or starting and stopping upon marked pressure difierentials, using the same general pilot mechanism in with the cam; and such an arrangement is shown inFigs.5,6and7. Inthesefiguresitwillbe observed that a transfer switch mechanism, gen-' erally designated 4G, is arranged in a generally vertical position and mounted at the left-hand end of the casing 60' of the pilot mechanism-P. The plunger 5 is shown in the same relative position as in Fig. 3, but instead of employing a cam rotating upon a horizontal shaft, as, in Figs.

1 and 3, the cam 'l4'is mounted upon a vertical shaft I3 which is coaxial with the switch arm 80 which carries the movable contact 49' and moves it selectively into engagement with the stationary contacts 41', 44' and 48', In Fig. 6, the switch arm 80 .is in the position for loadand-unload operation, and accordingly the cam, which is shown in the corresponding position in Fig. 7, is not effecting protrusion of the plunger 5. Further description of this simplified and more compact arrangement of the parts is unnecessary, as how it works will be obvious.

In Figs. 8, 9 and 10 a further modification shown, in which the transfer switch does not manually shift the cam, but in which instead a circuit is established through a solenoid which moves the cam for actuating the plunger 5' plunger 66' a guide 8!, in which there is reciprocable a cam-providing member, 86 providing a cam surface 81 at the bottom of a slot 88 into which the plunger I projects. A connection ll accuses attaches the cam-providing member 88 to the coreorphmgerilofanoperatingsolenoldfl, and aspring flnormallymaintainaexceptwhen said solenoid is energized, the cam in pomtion so that thepilot device P" operates on relatively small pressure changes. The solenoid Si is connected at one end, by a conductor 93, to a conductor ii which leads to one end of the transformer secondary u'; and the'other end of the solenoid is connected, by a conductor 9, to the contact element 41" of a switch 46''. The contact element 44" is connected by a conductor 95 to a conductor which connects the time delay relay with the end of the transformer secondary ll to which the conductor 5! does not lead. The same end of the transformer secondary 34 which is connected to the time delay relay by the conductor II is connected by a conductor 33 to the switch operating solenoid 32,. and the other end of the latter is connected by a conductor 11 through a conductor II with the time delay relay. and through a conductor 42 to a contact it which is connectable, in the closed position of a switch 91, with a second contact 95' electrically connected with the conductor 38 leading to the solenoid ll, and also connected by the conductor 53 to the switch M. The contact 4'" i8 anism P".

connected with the conductor 31, and the contact ll" with the conductor 5!. Further description of the connections is unnecessary in view of similaritytothesystemillustratedinFig. 1.

The mode of operation of this device can now bereadily understood. When the switch mechanism it" is operated to position the swingable contact element l!" in the position to connect contacts "and II", the motor will operate continuously and the compressor load and imload in accordance with the receiver pressure variations. It will be evident that circuits will be established connecting the transformer secondary 34, through the conductor 5|, contact l5", contact ll", contact 48'', conductor ll, motor switch operating solenoid 32, and conductor 33, to close and hold closed the motor starting switch;

.andalsothetimedelayrelayoperatingclrcuit will be energized as soon as the switch 4l";is actuated to effect the positioning specified, a conductor 4| leads to one end of the transformer secondary 34 whilethe other end of the transformer secondary is connected, through conductor I, contacts l5", l9" and I8", conductor 31,

and conductor II, to the time delay relay. The

solenoid II will be energized and de-energized, depending upon the operation'of the pilot mech- After the time delay relay operates. it will be evident that a circuit will be established from the left-hand end of the transformer sec.- ondary 34 through conductor ll, through the time delay relay, through conductor 39,.through the solenoid 30, through conductor 38, through conductor 53, and, when the switch M is closed. through that, and through conductors 54 and ii back to the transformer secondary, so that whenever the switch M is closed the compressor will be loaded, and whenever the switch M opens, the compressor will be unloaded. Accordingly, this system willoperate on the load-and-unload principle with relatively small pressure changes between loading and unloading.

When the switch mechanism It" is actuated to position the contact element-.1!" to connect contacts 41" and 'Zthe solenoid 9| will be energized continuously through a circuit including transformer secondary ll, conductor 5|, conductor-QS, the solenoid. conductor 94, contacts II". ll" and ll", and conductor 40. This will movethecamtl toincreasethepressurerange of the pilot mechanism P" and to make the some effective to move to switch-opening direction at the same maximum pressure, but to effect switch closure only at a considerably reduced presure, say, opening the switch M at 100 pounds and closing it again at 80 pounds. The upward movement of the cam will be accompanied by upward movement of the contact 91, which will then connect contacts 96 and it. As a result of this. there will be provided controlling circuits controlled by the switch M for the vmotor starting magnet 32, the time delay relay and the solenoid 30. Accordingly, when the receiver pressure becomes low enough, and the switch M is closed, the transformer secondary ll will deliver current to the motor starting switch solenoid 32 through a circuit including conductor 5|, conductor 54, switch M, conductor 53, contacts 96', l1, and 96, conductor 42, conductor 31, magnet 32 and conductor 33. Also, since conductor ll connects to conductor 42 and conductor ll connects to the left-hand end of the transformer secondary 34, operating current will be supplied to the time delay relay TDR simultaneously with current supply to the operating magnet 32. Current cannot be supplied to the solenoid-3| until the time delay relay operates to establish a circuit, and so.

in spite of the fact thata circuit is otherwise completely established through the solenoid ll upon closure of the switch M. thro h conductors II, 54, switch M, conductors 53, 38, solenoid ll, conductor 3! and conductor 40, the compressor will not be loaded lmtil the time delay relay operates. Accordingly, with this form of connection there will be stopp n of the motor.

and of the compressor each' time the compressor builds up, let us say, 100 pounds pressure in the receiver, and thereafter the compressor will remain out of operation until the receiver pressure drops to the lower level caused by the action of the cam 81, for example, 80 pounds.

It is obviously unnecesary to employ, in making avail of the broadest aspects of my invention, a.single pilot mechanism having provision for the eilfecting of a radical modification of its operatingrange; andaccordinglyinliig 151have illustrated another embodiment of the invention in which a pair of pilot devices selectively placed in control of the operation of the system are employed, these pilot devices being arranged to eifect \mloading upon the attainment of substantially identical upper receiver pressure limits but to effect .re-loading at markedly different lower receiverpressurelimits. InthissystemI may use pilot switches of the type generally illustrated in Figs. 11 to 14, but without the special lower limit adjustment of that switch.

In Fig. 11 there is shown a pilot mechanism which is essentially the well known commercial apparatus known as a Mercoid pressure control switch. This device includes a Bourdon tube III! which is adapted to operate, through mechanism mechanism. In the commercial device, a pair of.

adjusting elements like the element lfll are provided, and by manipulation of these elements the internal mechanism of the switch apparatus may be adjusted to vary the operating points.

For example, adjustment of the element marked t on the drawings changes the upper pressure limit and also changes the position of the finger II! so that the upper working pressure limit may be continuously known. Similar mechanism is provided in the standard Mercoid switch for appropriately formed cam [It s pported on a' bracket HI when it is desired to use a single Mercoid switchof this type, in a system such as v is illustrated in Fig.1, for example. It will be 20 evident that it is possible, since guides H2 are provided for the stem it! in a formic permit access to the knurled periphery IIt of the nut WI, to efiect adjustment of the position of the screw II! and so of the lower presure limit; 25 and by rotating the cam III at the same time that-the transfer switch is moved, the lower pressure limit may be increased or diminished as the control system changes from stop-andstart to load-and-unload, and vice versa. Since 39 it will be obvious how the cam m may be rotated in conjunction with the transfer switch,

from what has been previously illustrated, this arrangement needs no further description.

In Fig. 15 two such Mercoid switches are illustrated at we. and NR. In this case, however, the Mercoid switches are of the standard commercial type. and are not provided with the special attachment shown in Figs. ll, 12, 13 and 14. Switch WR is set to provide an upper op- 4o crating pressure or 100 pounds, let us'say, and a lower operating pressure of '80 pounds? while switch NR is set to provide an upper operating pressure of 100 pounds and a lower operating pressure of 95 pounds. Each of the switches WR 5 and NR is simply shown with diagrammatically represented connections, and it will be understood that upon the attainment of the upper Pressure limits for which the switch mechanisms are adjusted, the switches will open, and upon I 50 the lower pressure limits being attained, the

switches will close.

Now referring to the circuits of Fig. 15. it will beomertedthatatransiormerlihasaprhnary 26 connectedacrosstwootthepowerlinesand 55 a secondary it connected to the motor starting switch winding 32 by a conductor 23 and to a time delay relay TDR by a conductor it, as well as by a part of theconductbr 23. .A transfer switch is illustrated in Fig. 15.

60 at T andcompnse's a series of stationary contacts I20, I2I, I22, I23, I24, I25 and a pair of spaced movable contacts I26 and I2! connected for movement together. Any suitable operating means for this, switch'may be provided, and in 65 the upper position thereof contact I26 connects contacts I2! and l2i, while the contact I21. connects stationary contacts I24- and I25. In the other position of the switch, contact g I26 becomes inactive, but contact I2! connects to contacts I22 and I22. A conductor I30 connects the end of the transformer secondary 34 not previou'sly referred to, to contacts I20 and I22. A

conductor, Ill connects contact I2I to pilot mechanism WR, and the other side of this pilot 75 mechanism-is connected by a conductor I33 and a conductor I32 to contact I 23. A. conductor I" connects one side of the switch NR also to contact I23, and a conductor I35 connects the other side of switch NR. to contact I24. A conductor I3G "connects the first mentioned side of switch 5 NR to contact I25. Conductor ll is connected to the same side of switch NR as conductor I35. Conductor 31 is connected to contact I23.

The mode of operation at this apparatus may now be readily understood. Let it be assumed that the switch mechanism '1 is moved upwardly. This establishes connection between contacts I20 and I2I and between contacts I24 and I25. Accordingly, transformer secondary current will traverse-a circuit including the conductor I30,

contact I20, movable contact [26, contact I2I, conductor BI, the switch of WR when the latter is closed, conductor I33, conductor 31, motor switch winding 32, and conductor 33, and therefor obviously switch mechanism WR will; when closed, efiect closing of the-motor switch. Obviously, since the time delayrelay is connected by conductor 4| to conductor Si and by conductor It, to conductor 33, opening and closing of the switch WR will also open and close the circult of the time delay relay operating mechanism. When switchWRis closed andthetime delay relay operating mechanism is operated, a circuit willalso be established through the winding 3|! of the unloading-meehanism-controlled switch, including transformer secondary 2, conductor [30, contacts I21, I26 and l2t, conductor I I, conductor I33, conductor I34, conductor I36. contact I25, movable contact I21, contact I24,

conductor I35, conductor 38; the winding SI,

conductor 39, the time delay relay switch mechanism, and conductor II: and the compremor will loaded at the appropriate time after-the mot rhascomeuptospeed.

with this arrangement,- since the mechanism 40 WE is set for a wide pressure range, the system will operate to start the compressor and, after the same has had an opportunity to come up to speed; to load the latter upon theattainment of the desired relatively low minimum pressure, say 80 pounds per square inch; and will stop the compressor and cause unloading thereof at the desired upper pressure value, say 100 pounds.

Now, when it is desired to run the compm continuously with loading and unloading to maintain the receiver pressure within the desired limits, this may be accomplished by moving the switch mechanism T to its lower operating position. This will cause contact I21 to connect contacts I22 and I23 and place pressure switch mechanism HR in control. The motor switch will be closed and maintainedclosed by energization of the magnet 32 through a circuit including conductor 33, transformer secondary 34, conductor no, contact I22, contact I21, contact I23, and conductor 31. The time delay relay operating circuit will also be energized slncewohductors ll of a pump control system to increase the pressure range between interruption and resumption of pumping when delivery is to be controlled by stoppin and starting the compressor, and reducing the pressure range between interrupting and resuming pressure delivery when loading-andunloading is the method of control used. In all the forms illustrated, means is provided whereby the upper pressure limit may be maintained substantially constant if desired, notwithstanding the wide range of adjustment possible in the lower pressure limit.

While I have in this application specifically described several forms which my invention may assume in practice, and modifications thereof, it will be understood that these various forms are shown for purposes oi illustration only, and that the invention may be further modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a pump, a driving motor of which control means is eflfective, and for initipump is continuously operated for interrupting or causing pumping, means for rendering either of said means efiective to control'fluid delivery, and means common to both of said flrst two means for effecting control of the pumping'system by the pressure of the pumped fluid in either case, providing for interruption of fluid delivery at the same maximum delivered pressure, irrespective of which control means is effective, and for initiation of fluid delivery upon a less reduction in the delivered pressure when control,

is by said second mentioned means than when control is by said first mentioned means, said means including elements movable in predetermined relation'to each other for changing controls and delivered pressure minima,

3. In combination, a pump, a driving motor therefor, means for stopping and starting pump drive by the motor, means operative while the pump is continuously operated for interrupting or causing pumping, means for rendering either of said means efifective to control fluid delivery, and means for 'efiecting control of the pumping systembythepumpedfluidineithercase,providlng for initiation of fluid delivery upon a less reducti in the available quantity thereof when control by said second mentioned means than when control is by said first mentioned means and interruption of delivery for'the same available quantity during control by either means,

said fourth mentioned means comprising a.

pumped-fluid controlled device'having provision for varying the value of its lower operating limit.

4. In combinaidon, a pump, a driving motor therefor, means for stopping and starting pump drive by the motor, means operative while the pump is continuously operated for interrupting or causing pumping, means for rendering either of said means efiective to control fluid delivery, and means for efiecting control of the pumping system by the pumped fluid in either case, providing for initiation of fluid delivery upon a less reduction in the available quantity thereof when control is by said second mentioned means than .when control is by said first mentioned means and for discontinuation of fluid delivery at the.

same maximum available quantity irrespective of which of said first two control means is effective, said means fourth mentioned comprising a pair of pumped-fluid responsive devices having like upper settings and materially different lower settings.

5. In combination, a pump, a driving motor therefor, means for stopping and starting pump drive by the motor, means operative while the pump is continuously operated for interrupting or causing pumping, means for rendering either of said means effective to control fluid delivery, and means for efiect-ing control of the pumping system by the pumped fluid in either-case, providing for initiation of fluid delivery upon a less reduction in the available quantity thereof when control is by said second mentioned means than when control is by said first mentioned means but.interruption of delivery at the same available quantity, said fourth mentioned means including a pressure responsive device whose adjustment is automatically varied by the operation of said third mentioned means.

6Q In combination, a compressor, a driving motor therefor, means for starting and stopping the motor, means for loading the compressor and unloading the sa'me, means for rendering either of said means operative to control the output of the compressor, and pressure-responsive means having an adjustment controlled'by said third mentioned means for providing like limits for stopping the motor and for unloading the compresser and unlike limits for starting the motor and loading the compressor.

7. In combination, a compressor, a driving motor therefor, means for starting and stopping the I motor, means for loading the compressor and unloading the'same, means for rendering either of said means operative to control the output of the motor, means for loading the compressor and unloading the same, means for rendering either of said means operative to control the output of the compressor, and selectively operative pressure-responsive means providing like limits for 75 pressor and unlike limits for starting the motor andloading the compressor.

9. In combination, a compressor, a driving motor therefor, unloading means for said com- 101 responsive means for governing both loading and pressor, means for effecting stopping and starting means for rendering said pressure-responsive means selectively operative to control either loading and unloading or motor stopping and startv115 ing, and means for automatically varying the opcrating characteristics of said pressure-responsive means with the change from one control to the other.

10. In combination, a compressor, a drivingv 20 motor therefor, unloading means for said compressor, means for effecting stopping and starting of the driving motor,- means for effecting op eration of the unloading means to effect compressor unloading and loading, pressure-respon-* sive means for governing both loading and unloading and motor stopping and starting, a rotatable switch for rendering said pressure-rd sponsive means selectively operative to control- L either loading and unloading or motor stopping and starting, and means rotatable with said switch for automatically varying the operating characteristics of said pressure-responsive means with the change from one control to the other, to reduce the lower operating limit thereof when said pressure-responsive means is controlling said second mentioned means.

11. In combination, a compressor, a driving motor therefor, unloading means for said compressor, means for eirecting stopping and starting 40f of the driving motor, means for efiecting oper- 45 rendering said ation of the unloading means to effect compressor unloading and loading, pressure-responsive means for governing both loading and imloading and motor stopping and starting, a switch for pressure-responsive means selectively operative to control either loading and unloading or motor stopping and starti and cam means movable with said switch for automatically varying the operating characteristics of said 50 pressure-responsive means with th change from 55 and start is efiected.

5 five one control to the other to increase the diilerentie] between the operating limits of said pressureresponsive means whilemaintaining vone of them constant, when control by drivlng'i'motor stop I 70 other.

13. In combination, a compressor, a driving motor therefor, unloading'means for said com-- pressor, means for effecting stopping and starting of the driving motor, means for effecting op- 75 eration of the unloading means to effect com- I 2,221,855 stopping the motor and for unloading the conipressor unloading and loading, pressure-respom sive means for governing both loading and unloading and motor stopping and starting, means for rendering said pressure-responsive means selectively operative to control either loading and unloading or motor stopping and starting, and electromagnetically operated means for automatically varying the operating characteristics of said pressure-responsive means with thechange from one control to the other.

14. In combination, a compressor, a driving motor therefor, unloading means for said compressor, means for eiiecting stopping and startingot the driving motor, means for effecting operation of the unloading means to effect compressor unloading and loading, pressure-responsive means for governing both loading and unloading and motor stopping and starting, means for rendering said pressure-responsivemeans selectively operative to control either loading and unloading or motor stopping and starting, and electromagnetically operated cam means for automatically varying' the operating characteristics of said pressure-responsive means with the change from one control to the other.

15. In combination, a compressor, a driving motor therefor, unloading means for the compressor, a motor switch, operating means for the compressor unloading means and the motor switch respectively, pressure-responsive means controlling both of said operating means and providing the same upper operating limit and different lower operating limits, and means for selectively causing control of the output of the compressor through said unloading means by said pressure-responsive means providing the higher of the loweroperating limits and by said motor switch through said pressure-responsive means 16. In combination, a compressor a driving motor therefor, unloading means ior the-compressor, a motorswitch, operating means for the compressor unloading means and the motor switch respectively, pressure-responsive means controlling both of said operating means and providing the same upper operating limit and dlfierent lower operating limits, and switch means for selectively causing control oi the out-. put of the compressorthrough said unloading means by said premure-responsive means providing the higher of the lower operating limits and by said motor switch through said pressureresponsive means: providing the lower of the lower operating limits.

17. In combination. in a system, to be controlled, 'a device whose operation creates one critical condition in such system, and interruption of whose. operation permits the development in said system of a lower critical condition, and

means for etiecting the operationv of said to produce said first mentioned critical condition having controlling means providing for the selective rendering of said device operative to produce said first mentioned critical condition upon the attamment of diflerent lower critical [,conditions and eflective to interrupt operation of said device on attainment of the same upper critical condition.

18. In combination, a compressor. a driving motor therefor, means for starting and stopping said motor, means for unloading and eirecting reloading of said compressor, a .pressure responsive element having relatively adjustable operating limits. means for rendering it selectively eilective to control both o1 said first mentioned means or the second only in accordance with compressor discharge pressure, and means for automatically increasing the lower operating limit of said element when it is made effective to control said second mentioned means only,

while maintainingjts upper operating limit subw stantially unchanged.

19. In combination, a compressor, a driving motor therefor, means for starting and stopping said motor, means for unloading and efiecting reloading of said compressor, a time delay device associated with said second mentioned means, a pressure responsive element having relatively adjustable operating limits, means for rendering it selectively. effective to control each of said first two means and said device or said second mentioned means only, in accordance with compressor discharge pressure, and means for automatically increasing the lower operating limit of said element when it is made effective to control said second mentioned-means only, while maintaining its upper operating limit substan- 10 JESS M. BARTHOLOMEW.

tially unchanged.

CERTIFICATE OF CORRECTION. Patent No. 2,221, 55. November 19, 19m.

' JESS n. BARTHOLOI'IEW. It is hereby certified that error appears in the printed specification of the above numbe'red patent requiring correction as follows: age 1, sec- 0nd column, line 55, for the word "joint" read -point; page 5 first colmnn, line 8, for "collection" read ti line 51, for "receive" read -receiver--; page 8 first column, line 11, claim 9, strike out pressor, means for effecting stopping and starting and insert instead --unloading and motor stopping and starting,--; and that the said Letters Patent should be read with this correction therein that the same may con form to the record of the case in the Patent Office.

Signed and sealed this 51st day of December, A. D. 191w.

Henry Van Arsdale, (Seal) Acting Commissioner 'of Patents. 

